Tall oil is a mixture of mainly acidic compounds found in pine trees and obtained as a by-product of the pulp and paper industry. It is produced, for example, in the form of a resinous yellow-black oily liquid as an acidified byproduct in the Kraft or sulfate processing of pine wood. Tall oil, also known as “tallol” or “liquid resin”, prior to refining, is normally a mixture of rosin acids, fatty acids, sterols, high-molecular weight alcohols, and other alkyl chain materials (i.e. rosin acids, fatty acids, and unsaponifiables or “neutral compounds”). Distillation of crude tall oil can be used to recover a mixture of fatty acids in the C16-20 range. Commercially available tall oil products XTOL® 100, XTOL® 300, and XTOL® 304 (all from Georgia-Pacific Chemicals LLC, Atlanta, Ga.), for example, all contain saturated and unsaturated fatty acids in the C16-20 range, as well as minor amounts of rosin acids. It should be appreciated that, as tall oil is derived from a natural source, its composition can vary. The main fatty acids found in all tall oils, however, are oleic, linoleic, stearic, and palmitic acids.
Tall oil has a variety of uses in industry. For example, it can be used as a frothing agent in the flotation process for reclaiming low grade copper-, lead-, and zinc-bearing ores, and as a solvent or wetting agent in a variety of textile and synthetic fiber manufacturing processes. The distilled fatty acids can be used in soaps, detergents, and disinfectants and as a base for lubricating greases, textile oils, cutting oils, and metal polishes. Rosin acids can be used in rubber polymerization and compounding, as size to impart water resistance to paper, and in adhesives and printing inks.